th th On June 17 and 18 1987 the fourth workshop on "Azospi rillum: Genetics, Physiology, Ecology" took place at the Uni ver sity of Bayreuth, West Germany, organized by the Genetics depart ment. There were about 80 participants, who came from German research institutions, from other European countries, from Is rael, Egypt, India, North Vietnam, and North and South America. The former workshops had also taken place in Bayreuth, in 1981, 1983 and 1985, hence the organizers could draw on the experience obtained at these earlier workshops. Azospirilla have, during the past 15 years, found an ever increasing scientific interest because, first, these soil bacte ria carry the genetic information for binding molecular nitrogen from the air and, second, they live in close vicinity to the roots of grain crops and forage grasses. By exploitation of these two properties, it is hoped to develop inoculation procedures which can be used in nitrogen-deficient soils.

th st On June 20 and 21 1985 the third workshop on "Azospirillum: Geneties, Physiology, Eeology" took place at the University of Bayreuth, West Germany, organized by the geneties department. There were about 80 partieipants, who eame from German research institutions, from other European eountries, from India, Egypt, North and South America. The former workshops had taken place in Bayreuth too in 1981 and 1983 respeetively, henee the organizers eould draw on the experienees then obtained. Azospirilla have, during the past 12 years, found an ever inereasing seientifie interest, beeause first, these soil baeteria earry the genetie information for binding moleeular nitrogen from the air, and second, they live in elose vieinity to the roots of grain erops and forage grasses. By exploi tation of these two properties, it is hoped to develop inoeulation proeedures in soils poor in nitrogen. The reports on the first afternoon foeussed, as aresult of the Bayreuth research interest, on genetie approaehes.

This thorough study is an assessment of the risks involved with the deliberate release of microorganisms modified by means of genetic engineering. Major emphasis is on European cooperative research projects such as the ones on Rhizobium and Baculovirus. Further contributions cover aspects of soil microbiology, genetic transformation in soil, molecular and plasmid genetics, horizontal spread of plasmids, as well as administrative, regulative and legal aspects in relation to possible releases.